Okay. I rechecked everything. Lubed. Torqued properly. Removed the 1mm spacer leaving behind the 1.85 and the tolerances looked better. Just like old setup. And everything seems fine. But this random and startling clang still occurs. It's not normal because I can't recreate it easily. The engagement of the hub is silent compare to this noise. I notice it's more apparent with more force being applied to the pedal. But it only happens after I coast then start applying force again. But not every time. I'd not know where to begin but I've only noticed since I changed to the new wheel set. Caad9 optimo 1. dura ace and ultegra mix. I'll take it to LBS tomorrow because I can't stand it. It's almost like something is moving 1mm with enough force to resonate through the bike. It happens in any combination of gearing. Rear axle is tight. Nothing else has changed other than wheelset.